The present invention is directed to a processing apparatus of the type which generally include upper and lower tanks for holding a processing fluid and a narrow processing chamber located between the tanks through which a sheet of photosensitive material is advanced for processing of latent images on the material. Processing fluid is delivered to opposite sides of the photosensitive material from each of the tanks for forming a processing fluid layer on each side of the photosensitive material. A return drain is provided on each side of the photosensitive material for removing and returning the processing fluid to the sump tank. Example of such devices are illustrated in U.S. Pat. No. 4,989,028; U.S. Pat. No. 4,994,840; and U.S. Pat. No. 5,059,997. Such devices are often referred to as fluid suspension processors.
In fluid suspension processors of the type illustrated in U.S. Pat. No. 5,059,997, processing fluid is pumped from a sump tank into the lower tank and is allowed to freely flow from the lower tank to the upper tank. During initial start up of the processor, a significant amount of processing fluid must be pumped into the tanks, thus significantly lowering the level of the processing fluid in the sump tank. This results in the processing fluid in the upper tank cascading a large distance when returning to the sump tank which in turn results in bubbles forming due to the high agitation in the processing fluid. This high agitation can significantly reduce the available chemistry in the processing fluid and thereby increase the total amount of chemistry used by the processor per unit of film. Additionally the lowering of the processing fluid in the sump tank results in a large quantity of fresh replenishment solution be supplied to the sump tank. This provides a large quantity of new chemistry for processing of photosensitive material. However, the processor still continue to add additional replenishment solution in accordance with the amount of photosensitive material that is processed. This results in significant reduction in the efficient use of the available chemistry in the processing fluid.
The present invention is directed to solving the problems of the prior art by providing means for minimizing the distance the processing fluid must travel to the sump tank and for the efficient utilization of the new chemistry added to processing fluid.